Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms.
We have used isoform-specific antibodies against the Na+, K(+)-ATPase alpha (alpha 1, alpha 2 and alpha 3) and beta (beta 1 and beta 2) subunit isoforms in order to establish their specific localization in isolated bovine articular chondrocytes. Immunoblotting confirmed the presence of the alpha 1 a...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
| Published: |
1997
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| _version_ | 1797087635503579136 |
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| author | Mobasheri, A Errington, R Golding, S Hall, A Urban, J |
| author_facet | Mobasheri, A Errington, R Golding, S Hall, A Urban, J |
| author_sort | Mobasheri, A |
| collection | OXFORD |
| description | We have used isoform-specific antibodies against the Na+, K(+)-ATPase alpha (alpha 1, alpha 2 and alpha 3) and beta (beta 1 and beta 2) subunit isoforms in order to establish their specific localization in isolated bovine articular chondrocytes. Immunoblotting confirmed the presence of the alpha 1 and alpha 3 isoforms, although alpha 1 expression was significantly greater than alpha 3 as assessed by immunofluorescence confocal laser scanning microscopy and PCR. A similar approach revealed the presence of the beta 1 and beta 2 isoforms in chondrocytes, although beta 2 immunostaining on the plasma membrane was more punctate than beta 1 which in contrast predominated in a subcellular compartment. The plasma membrane abundance of the Na+, K(+)-ATPase was found to be sensitive to the extracellular ionic concentration and long-term elevation of extracellular Na+ concentration significantly upregulated Na+, K(+)-ATPase density as measured by specific 3H-ouabain binding. Our observations suggest that the expression of alpha 3 and beta 2 is not restricted to excitable tissues as previously reported. The physiological relevance of alpha 3 expression in chondrocytes may be related to its low affinity for intracellular Na+ in an extracellular environment where Na+ concentration is unusually high (260-350 mM) compared to other cell types (140 mM). Glycoproteins and their branched carbohydrates have been implicated in cell recognition events, thus the beta 2 subunit glycoprotein may allow the chondrocyte to detect changes in its extracellular environment by physically interacting with components of the cellular cytoskeleton and matrix macromolecules. |
| first_indexed | 2024-03-07T02:38:28Z |
| format | Journal article |
| id | oxford-uuid:a99c1ec9-c70d-433b-a65f-fa860b7073d6 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T02:38:28Z |
| publishDate | 1997 |
| record_format | dspace |
| spelling | oxford-uuid:a99c1ec9-c70d-433b-a65f-fa860b7073d62022-03-27T03:09:35ZCharacterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms.Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:a99c1ec9-c70d-433b-a65f-fa860b7073d6EnglishSymplectic Elements at Oxford1997Mobasheri, AErrington, RGolding, SHall, AUrban, JWe have used isoform-specific antibodies against the Na+, K(+)-ATPase alpha (alpha 1, alpha 2 and alpha 3) and beta (beta 1 and beta 2) subunit isoforms in order to establish their specific localization in isolated bovine articular chondrocytes. Immunoblotting confirmed the presence of the alpha 1 and alpha 3 isoforms, although alpha 1 expression was significantly greater than alpha 3 as assessed by immunofluorescence confocal laser scanning microscopy and PCR. A similar approach revealed the presence of the beta 1 and beta 2 isoforms in chondrocytes, although beta 2 immunostaining on the plasma membrane was more punctate than beta 1 which in contrast predominated in a subcellular compartment. The plasma membrane abundance of the Na+, K(+)-ATPase was found to be sensitive to the extracellular ionic concentration and long-term elevation of extracellular Na+ concentration significantly upregulated Na+, K(+)-ATPase density as measured by specific 3H-ouabain binding. Our observations suggest that the expression of alpha 3 and beta 2 is not restricted to excitable tissues as previously reported. The physiological relevance of alpha 3 expression in chondrocytes may be related to its low affinity for intracellular Na+ in an extracellular environment where Na+ concentration is unusually high (260-350 mM) compared to other cell types (140 mM). Glycoproteins and their branched carbohydrates have been implicated in cell recognition events, thus the beta 2 subunit glycoprotein may allow the chondrocyte to detect changes in its extracellular environment by physically interacting with components of the cellular cytoskeleton and matrix macromolecules. |
| spellingShingle | Mobasheri, A Errington, R Golding, S Hall, A Urban, J Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms. |
| title | Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms. |
| title_full | Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms. |
| title_fullStr | Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms. |
| title_full_unstemmed | Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms. |
| title_short | Characterization of the Na+, K(+)-ATPase in isolated bovine articular chondrocytes; molecular evidence for multiple alpha and beta isoforms. |
| title_sort | characterization of the na k atpase in isolated bovine articular chondrocytes molecular evidence for multiple alpha and beta isoforms |
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